3D Printers Now Printing Muscles

3D printers, normally utilized in the fields of architecture, aerospace engineering and materials science, boast a new application in a field that one might not expect. Usually, 3D printers are used to rapidly create prototypes of new structures without ever having to cast a mold to do so. For instance, a hand-crafted gargoyle (similar to those fashioned on cathedrals) could be scanned by associated software after which the 3D printer would make an exact replication of the figurine using an inexpensive resin.
Thanks to the recent breakthrough Organovo, a San Diego-based start-up company, 3D printers are now able to successfully print thin layers of human muscle in an arrangement such that the cells are allowed to grow to form working tissue. Unlike other approaches to deposit cells using printers, their technology has successfully allowed cells to interact in much the same way that cell do when building new tissue (in the body). Like growing tissues in the body, Organovo’s technology allows cells to adhere and exchange chemical signals with each other after deposition thereby crossing the bridge (so to speak) between growing a cell culture and growing a functioning tissue.

While putting cells into specially-made cartridges and putting them into the 3D printer seems simple enough, the novel process (unique to Organovo) of preparing the cells so that they behave like human cells after deposition is what has made this biomedical advancement possible. First, like most biological labs, the researchers must grow the cell culture first before applying an enzyme that frees the cells from the growing surface. Next, the cell culture is packed into dense pellets and are then sucked up through a glass capillary tube and incubated. The step of keeping the cells confined is what allows the cells to start to interact with each other. Once the cells are a discernable unit, they are freed from the tubes and submerged in nutrient-rich “broths” that allow the cells to grow, feed and interact similar to building new tissue in the body. After this phase of growth, the cells are then sucked back up the glass capillary tubes which now serve as ink cartridges. Using 3D printing software, the shape in which the cells are deposited can be programmed such that they are arranged in conformations normally found in the body. The printer then deposits the cells, one line at a time, onto an inert gel in a distinct pattern that was previously programmed. After longer periods of incubation, Organovo found that this pattern of cells would grow and congregate to form a single piece of tissue.

Needless to say, such a procedure has taken the field of tissue engineering by storm. This method can potentially render other tissue-growing techniques obsolete due to its simplicity and cost-effectiveness. For one, current tissue engineering techniques requires the synthesis of a “simulated biological environment” tailored to each cell type. Unlike the accepted procedure mentioned, 3D printers have the flexibility to grow a variety of cell types. A more immediate outcome of Organovo’s success is the promise of using these tissues in drug trials. With these simulated tissues being almost indistinguishable to extracted human tissue, Organovo’s new method would be instrumental in identifying drugs that would fail long before reaching clinical trials; this would save drug companies billions of dollars. With the intention of proving that this technology can detect drug toxicity earlier than other methods, Organovo, not surprisingly, is planning to fund this research by getting major partnerships with companies starting with the pharmaceutical Goliath, Pfizer.